filling in holes in the mast?

[Brion Toss]

Hi,
1. If the fitting was filled with machine screws, just put the screws back into the hole
2. If they were rivets, put rivets in. Aluminum ones. You could also use these for screw replacement, if it is easier, and the rivets will be less visually intrusive.
3. Thickened epoxy, sanded and painted, if looks matter that much.
Fair leads,
Brion Toss